The present invention relates to electrical contact pins and, more particularly, to an electrical contact pin having a compliant part.
Electrical contact pins having a compliant part to be fitted into a plated hole of a printed circuit board for mechanical fixation and electrical connection thereto are well known. FIGS. 15 and 17 show two examples of conventional compliant electrical contact pins.
The electrical contact pin of FIG. 15, so called "eye of the needle" compliant pin, is made by stamping from a sheet of springy conductive metal so that it has an opening 11 at the center of a compliant part 10 to give a spring property to the compliant part. As FIG. 16 shows this compliant part is fitted into a plated aperture 1 of a circuit board so that its four corners 11A elastically cut into the conductive wall of the plated aperture 1 for mechanical fixation and electrical connection thereto.
The electrical contact pin of FIG. 17 is made by first stamping out a compliant part 20 from a sheet of springy conductive metal. Then, the compliant part 20 is sheared to form a pair of legs 21 and 22. These legs are then offset with respect to each other along the shear plane so as to give a spring property to the compliant part. As FIG. 18 shows, the compliant part is fitted into a plated aperture 2 of a circuit board so that a corner 21A of the offset leg 21 and a corner 22A of the offset leg 22 elastically cut into the conductive wall of the plated aperture 2 for meachincal fixation and electrical connection.
Recently, electronic parts are densely mounted on a circuit board, and the diameter of plated apertures has become smaller than before. Consequently, there is a need to make the compliant part of an electrical contact pin smaller than before. However, it is practically impossible to punch out an opening 11 having a diameter of less than about 0.60 mm (0.024 inch) in the compliant part of an eye of the needle compliant pin of FIGS. 15 and 16. Although the compliant part of a contact pin of FIGS. 17 and 18 is relatively well fitted into a small aperture, there are only two points in contact with the conductive wall of a plated aperture, as shown in FIG. 18, and the contact pin tends to turn in fitting operation. Consequently, the fitting operation requires an extra force to counter the turning force.